Track-jack



(No Model.)

1-". ROBINSON.

TRACK JACK.

, No. 558,881. Patented Apr. 21-, 1896 Wain/1 730151216017,

.Pnoroumawunmsron.

NlTED STATES ATENT Oriucn.

FRANK. ROBINSON, OF BANGOR, MAINE, ASSIGNOR OF ONE-HALF TO ARTHUR O.NORTON, OF BOSTON, MASSACHUSETTS.

TRACK-JACK.

SPECIFICATION forming part of Letters Patent No. 558,881, dated April21, 1896. Application filed August 20, 1895. Serial No. 559,878. (N0 mdBL) To aZZ whom it may concern:

Be it known that I, FRANK ROBINSON, a citizen of the United States,residing at Bangor, in the county of Penobscot and State of Maine, haveinvented certain new and useful Improvements in TrackJacks, of which thefollowing is a specification, reference being had therein to theaccompanying drawings.

The object of my invention is to produce a track-jack which, while beingof simple and strong construction, contains all the desirable featuresof track-jacksthat is, easy and rapid lifting, secure holding, and aneasy and absolutely sure drop under all conditions of service. Thefeature that a track-j ack should have an easy and absolute sure drophas never been given heretofore the necessary attention, and in thisparticular my invention embodies an important improvement in that it canbe easily and instantly dropped under all conditions, or that if anemergency, such as a fast approaching train requires it, it can bespeedily removed from the track and thus avoid accidents, like the onewhich occurred on the Old Colony Railroad in August, 1890, near Quincy,Massachusetts, due to the lack of this feature in the track-jack.

My construction of track-jack is also particularly devised to simplifyand cheapen its construction and permit the use of good workmanship, allas more fully hereinafter deseribed,and shown in the drawings,in whichFigure 1 is a perspective view of my trackjack. Fig. 2 is a verticalsection of the upper portion thereof. Fig. 3 is a detached perspectiveview of the lever-socket and lifting-pawl. Fig. 4 is a side elevation ofthat portion of the jack to which the trip is applied, showing the partsas in operation.

The body of the jack is made of malleable iron in two parts. One partcomprises the base A, cast solid in one piece with the upright part A,forming three sides of the casing inclosing the lifting-bar, the fourthside being formed by the part A firmly riveted upon a solid foot at,extending above the base. The two parts A A are each accurately milledand firmly joined together.

Bis the lifting-bar, made from best quality of forged steel and providedupon opposite sides with vertical guide-grooves c, engaging withcorresponding ribs formed on the inside of the casing. The lifting-baris provided on the front side with a series of teeth 61, with which aholding-pawl is adapted to engage, and the rear side is provided with aseries of teeth c, with which a lifting-pawl is adapted to engage.

At the lower end the lifting-bar is integrally formed with aright-angularly-proj ectin g foot 13, which projects through a verticalslot formed in the front side of the casing, and the top of the barisprovided with the circular cap B roughened upon its upper face. Thefoot 13 of the lifting-bar has a housing formed in the top of the baseby means of a standing-flange b, integrally formed with the base A andextending to such a height as to wholly receive the foot B of thelifting-bar when the latter is dropped.

The mechanism for lifting consists. of a lifting-pawl O, which, by meansof a strap 0, is sleeved upon an eccentric D, integrally formed with thelever-socket E of the liftinglever. This lever-socket is made with theforked ends E E and is pivotally secured by means of a hardened toolsteel pin F, which is keyed to the frame so that it cannot turn to therearwardly-extending flanges A of the sides of the casing, all in suchmanner that the pin E forms the fulcrum for the forked ends of the leverand gives the eccentric sufficient throw to raise the lifting-bar fromonehalf inch to one and a half inches, as may be desired, with onestroke of the lever. To make it impossible for the pawl to becomedisengaged while lifting, the teeth in lifting side of bar are cutsquare.

G is the holding-pawl, pivotally secured by a steel pin H upon the frontside of the lifting-bar between two forwardlyprojecting ears I of thecasing. The holding-teeth of the bar are cut in line with the arc of acircle struck from the center of the pin H for the purpose hereinafterdescribed.

The holding-pawl is provided at one side of the casing with an extensionK, to which is pivotally secured the tripping-cam L in such manner thatit is free to swing on the side of the casing, so that it may be thrownin or out of engagement with a projection E on the forked arm E of thelever. The function of this tripping-cam is, first, to act as a weightto hold the holding-pawl in safe engagement with the lifting-bar by theaction of gravity, and, second, to form a means for instantaneouslytripping the jack, which is accomplished by raising the lever,disengaging the liftingpawl and turning the tripping-cam into position,as shown in Fig. 4, and then pressing down the lever. The end E of thelever in striking against the face of the tripping-cam forces theholding-pawl out of engagement with the lifting-bar, whichinstantaneously drops. The tripping-bar is provided with an inclinedface L of such character that it is thrown up by the lever with theforce of a wedge, which, aided by the shape of the teeth on thelifting-bar, is so powerful that a man can easily and instantly tripwith one hand any load that can be raised with the jack, even with twoor three men 011 the lever. In thus tripping the jack it will be seenthat there is no lifting of the load while it is being tripped, as isthe case with other jacks, and this feature constitutes a valuablefeature in this class of devices.

While it is not new in lifting-jacks to use an eccentric device forlifting, I still claim that my construction embodies a novel feature inthat the eccentric D is formed separately on one side of the arm E ofthe socketlever. This construction permits of proportionin g andlocating the eccentric to give the best results. The arm E being shapedbroad and fiat, as shown, furnishes a strong bearing for the pin in theeccentric, and therefore this pin may pass as close to the periphery ofthe eccentric as may be desired without weakening the bearing of thelever in any degree. Thus, with a comparatively small eccentric, thegreatest desirable throw can be obtained with the least amount offriction.

I find it desirable to provide the trippingcam with some means forholding it from accidental displacement when turned into its operativeposition. To this end I show in the drawings in Fig. 4 a smallcoil-spring M, seated in a recess of the extension K of the dog andpressing against a flat portion on the hinge-knuckle of thetripping-cam, all so arranged that the tension of the coil-spring holdsthe cam either in the position shown in Fig. 1 or in the workingposition shown in Fig. l.

\Vhat I claim as my invention is- 1. In a track-jack, the combinationwith the supportingcasing, of a lifting-bar provided with ratchet-teethupon front and rear,a holding-pawl engaging with the ratchet-teeth uponthe front thereof, a tripping-cam hinged thereto free to swing on theside of the casing a lifting-pawl engaging with the ratchet-teeth on therear of the lifting-bar and an operating-lever actuating saidlifting-pawl and pro vided with a forward extension adapted to engagewith the tripping-cam and trip the holding-pawl, substantially asdescribed.

2. In atrack-jack, the combination with the supporting-casing and thelifting-bar slidingly engaging therein and provided with ratchet-teethupon front and rear, a holdingpawl engaging the teeth on the front, alifting-pawl engaging with the ratchet-teeth upon the rear of thelifting-bar and provided with an eccentric-strap, an operating-leverprovided with a socket fulcrumed at its inner end to the rear side ofthe casing and an eccentric formed upon one side of the leversocket andhaving the strap of the lifting-pawl sleeved upon it, substantially asdescribed.

3. In a track-jack, the combination with the supporting-casing and itsvertically-slidable lifting-bar, of a holding-pawl engaging thelifting-bar upon the front side of the casing and having a tripping-camhinged thereto which is adapted to be turned rearwardly against the sideof the casing, a lifting-pawl engaging the lifting-bar upon the rearside of the casing, and an operating-lever provided with a socket havinga forked inner end ful- I crumed upon rearwardly-extending flanges of Ithe sides of the casing, one of the forked ends of said socket extendingforwardly on one side of the casing, and adapted to engage with and tripthe holding-pawl and the other being, enlarged and flattened andprovided upon its outer side with an eccentric-bearing upon which thelifting-pawl is sleeved, substantially as described.

4;. In a track-j ack, the combination with the lifting-bar havingratchet-teeth in front and rear and provided with verticalguide-flanges, and a foot I5, of the outer casing in which saidlifting-bar slidingly engages, said outer casing consisting of the partA, inclosing the lifting-bar upon three sides and cast integrally with abase A, forming a housing I) for the foot of the lifting-jack, and thepart A forming the fourth side of the casing and secured upon a foot aabove the base, substantially as described.

5. In atrack-jack, the combination with the casing and thelifting-barslidingly engaging therein, of the holding-pawl G pivoted in front tosaid casing, the ratchet-teeth d formed in the front side of the casingand having their faces cut in line with a circle struck from the centerof the holding-pawl, the tripping-cam L hinged to the holding-pawl andhaving the inclined face L as described, the ratchet-teeth e cut uponthe rear side of the lifting-bar, the lifting-pawl 0 adapted to engagetherewith, and the operating-lever socket E provided with the forkedends E E one formed with an eccentric carrying the lifting-pawl, theother having the extension E adapted to operate the tripping-cam,substantially as described.

6. In a track-jack the combination of the operating-lever carrying thelifting-pawl and provided with the extension E projecting beyond itsfulcrum On the side of the casing, the holding-dog provided With theextension K, the tripping-cam hinged to the extension K

